Journal of the History of Philosophy

The Role of Perceptual Relativity in Berkeley's Philosophy ROBERT MUEHLMANN IT IS SURELYa mark of the complexity of the issues involved, as much as the boldness and originality of their author, that while Berkeley's two major works are among the most lucid in the philosophical literature, they have been among the most often misunderstood. The high calibre of recent Berkeleyan scholarship has done much to rectify this sorry state of affairs, but on the title issue, or so I will argue, misinterpretations are quite common. The question of interpretation here is the use to which Berkeley puts the Argument from Perceptual Relativity (APR); or to say the same thing differently, at issue here is the nature of Berkeley's APR, specifically, the precise nature of the conclusion Berkeley thinks it establishes. The disputants in this quarrel can conveniently be characterized as, on the one side, those who propound the negative interpretationdthat the only use to which Berkeley puts APR is ad hominem-and those who, on the other, propound a positive interpretation. I say "a" positive interpretation because there is some divergence among the latter as to exactly what is the positive role Berkeley assigns APR. And while some positive reading is currently almost universal among the interpreters of Berkeley's philosophy, I shall not concern myself with the divergences among its proponents , since I shall argue in what follows that the negative view is correct and that any positive interpretation must be mistaken. 1 l Of the prominent interpreters of Berkeley's philosophy, only A. A. Luce champions the negativeinterpretation. See "Berkeley'sExistencein the Mind,"Mind 5o, 199 (July, 194l): 95867 ; Berkeley'sImmaterialism (Edinburgh, 1945) and, more recently, "Berkeley and the Living Thing," Hermathena193(1977): 19-95, esp. 19-91. On the other side,among the proponents ofa positiveinterpretation, are E. B. Ailaire, "Berkeley'sIdealism," Theoria(1963): 999-44, esp. 937; G. J. Warnock, Berke/ey(London, 1969),Chap. 8, esp. 146ff.;Philip D. Cummins, "Perceptual Relativityand Ideas in the Mind,"Philosophyand PhenomenologicalResearch94 (~963): 9o9-14, esp. [3971 398 JOURNAL OF THE HISTORY OF PHILOSOPHY 29:3 JULY t99t While the precise nature of APR is the matter of dispute, it is nevertheless certain that the argument contains, as its central premise, a statement of the fact of perceptual relativity (PR): The determinate sensible quality one immediately perceives an object to have varies with the conditions, both internal and external to the perceiver, under which the object is perceived. It is this fact, PR, specified to a given parameter of sensible qualities, which is at least implicit in each of Berkeley's applications of APR in the Principles and Dialogues? Whatever else may be the case about APR, it is certain also that Berkeley accepts PR--provided that 'object', 'internal', and 'external' are understood in the sense of "the vulgar," that is, in the sense in which the plain man uses them, and provided that 'immediately' is understood in Berkeley's philosophical sense. Since the appreciation of PR is so crucial to the title issue, both of these provisos are worth amplifying. First. At the beginning of the Dialogues, Berkeley takes pains to suggest that it is not the existence of what the plain man means by 'material substance' that he denies; rather he is claiming that "there is no such thing as what philosophers call material substance" (17 2, first italics mine). Berkeley holds that the plain man's use of noun substantives like 'object', 'external object', or even 'substance' and 'material substance' (Pr. 37) are ontologically neutral uses. That is, they are uses behind which there is no philosophical theory of the ultimate existents. It is not the ordinary use of such terms to which Berkeley objects. Indeed, it is largely because certain philosophical uses of these terms lead some philosophers to skepticism and violations of common sense that Berkeley objects to them. Second. By 'immediate perception'~ Berkeley means the sort of awareness ~1o; Konrad Marc-Wogau, "The Argument from Illusion and Berkeley's Idealism," in C. B. Martin and D. M. Armstrong, eds., Lockeand Berkeley(Notre Dame, 1968), 338-52, esp. 345; Alan Hausman and David Hausman, "Hume's Use of Illicit Substances," Hume...